For owners of the Pro-Cart AT1 all-terrain installation cart by Omni Cubed, the Multi-Top Accessory provides even more uses for their cart. The accessory uprights can be quickly clamped in, or removed from the cart according to transport needs. When the uprights are added to the cart, multiple smaller countertops can then be transported simultaneously to save time. Installers are now able to use their Pro-Cart AT1 for safely transporting larger tops, then on the second trip, the uprights can be added and the cart loaded with the smaller pieces. The uprights feature elongated and padded rails for full support of countertops, and a balanced design to prevent tipping of the cart. The lightweight aluminum uprights are also compact for easy storage in the install van or truck; each set includes one pair of upright support rails (two uprights are used per cart).